Simultaneous Gravel Packing and Filter Cake Removal in Horizontal Wells Applying Shunt Tubes and Novel Carrier and Breaker Fluid

摘要

Gravel packing long horizontal sections is an exceptionalrnchallenge in itself due to the lengths now being completed.rnWhen simultaneous gravel packing and effective mud cakernremoval is considered, the complexity of the process isrncompound, posing a more demanding challenge to therncompletion process. Previously, to gravel pack a horizontalrnwell it was necessary to seal off the wellbore from thernformation to such an extent that substantial circulation couldrnbe maintained during gravel packing. This implied the need ofrna filter cake in place that needed to be removed in a separaterntreatment after the gravel packing operation to achieve anrnefficient completion. The introduction of screens with shuntrntubes eliminates the need for well circulation during the gravelrnpacking operation, and therefore simultaneous removal of thernfilter cake while gravel packing becomes a viable possibility.rnIn this paper we present an integrated approach to gravelrnpacking and removal of the drill-in fluid filter cake. This wasrnachieved by a combined application of a surfactant basedrncarrier fluid in an enzyme and chelant breaker solution usingrnshunt tubes for open-hole gravel packing. The shunt tubesrnensure complete packing by allowing an alternate path forrnbypassing sand bridges that may form in the screen andrnformation annulus, due to excessive leak off. The carrierbreakerrnfluid ensures contact of the breaker with the filter cakernin the entire interval during and after gravel packing.Clean up efficiency tests, fluid rheological behavior andrnfluid design are presented together with field case histories.rnThese case histories demonstrate that gravel pack placementrnand well productivity index have been improved with respectrnto previous practices, while simultaneously reducing overallrncompletion cost.